| Congresso Brasileiro de Microbiologia 2023 | Resumo: 1156-1 | ||||
Resumo:Extraintestinal pathogenic Escherichia coli (ExPEC) strains are known to cause infections outside the gastrointestinal tract in humans, farm animals, and pets. Among the ExPEC sub-pathotypes, Newborn Meningitis-Causing E. coli (NMEC) has emerged as a major cause of neonatal meningitis in premature neonates with very low birth weight (<1.5 kg) over the last three decades. However, the epidemiological knowledge of NMEC is predominantly based on data from developed countries. To address this gap, the present work aims to establish a collection of genomically characterized NMEC strains from Brazil. A total of 62 NMEC isolates were collected from the cerebrospinal fluid of ill patients, including 12 from São Paulo (Institute Adolfo Lutz (IAL)), 38 from Bahia (UFBA), eight from Paraná (LACEN-PR), three from Minas Gerais (LACEN-MG), and one from Porto Alegre (HCPA). Phylogenetic analysis using pulsed-field gel electrophoresis (PFGE) revealed five pairs of clones, four among UFBA isolates, one among LACEN-MG isolates, and one among IAL isolates, with a diverse profile observed in the remaining isolates. The DNA of these NMEC isolates was extracted using a ThermoFisher kit and subjected to Illumina sequencing. Among the isolates from IAL and HCPA, 12 genomes have already been characterized (manuscript in preparation), while the remaining isolates (n = 50) were sequenced at INTA – CIMMYT in Argentina-Mexico, using Illumina NovaSeq 6000. At the moment the genomes are being assembled with SPAdes after having been trimmed on the Trimmomatic software and will be annotated using Prokka, and the core and pangenome will be identified using Roary software. Subsequent in silico analysis will include determining the phylogenetic status, serotype, multilocus sequence type (MLST), and presence of ExPEC-associated virulence genes. In parallel to the genomic characterization, phenotypic analyses of ExPEC-associated virulence traits, such as type 1 fimbriae and siderophore production, are being conducted. Production of type 1 fimbriae was assessed by yeast agglutination assays. Six isolates from São Paulo, 20 from Bahia, and five from Paraná showed agglutination, indicating the presence of type 1 fimbriae. However, the fact that 27 isolates did not agglutinate (4 isolates should still be tested) raises the possibility that type 1 fimbriae may not be crucial for blood-brain barrier (BBB) crossing in these NMEC strains. The acquisition of iron by a pathogen within mammalian hosts during infection is essential for the pathogen's successful pathogenesis. Siderophore production has been analysed using the Chrome azurol S (CAS)-agar assay. Among the 24 isolates tested, 22 isolates were able to uptake iron from CAS agar medium. The significant number of bacteria evaluated thus far, capable of capturing iron from the medium, suggests that the presence of siderophores could be an important virulence factor in meningitis caused by Escherichia coli. Overall, this project represents a crucial effort to expand our understanding of NMEC genomic epidemiology in Brazil and provide essential genomic and phenotypic data for further studies. By comparing Brazilian NMEC strains with known ExPEC model strains, this research may shed light on the pathogenicity and virulence mechanisms of NMEC and contribute to the development of targeted interventions to combat neonatal meningitis caused by these bacteria. Palavras-chave: Escherichia coli, Genomic Epidemiology, Neonatal meningitis, PFGE, Whole Genome Sequence Agência de fomento:CAPES e PPSUS/FAPERGS | |||||